Pre-Story: About 2 weeks ago I drove my 2013 WRX through a dry sandy valley, when a large bit of wind kicked up the light sand that was piled on the side of the canyon, aside from coating the front of my car in a thin sandy coat I was sure that I sucked up a good bit, When I was washing/waxing the WRX over the weekend I noticed that the air dam on the front bumper had gotten rather muddy from the wash and when I removed it for cleaning I could see the same muddy brown crud coating a large portion of the panel filter. I went down to my local autoparts store and found 4 panels that fit, 3 were paper filters much like the OEM and 1 was a fiberglass filter that required oiling. After reading numerous CIA threads I decided that oiled filters were not for me and decided to go with a dry type panel filter. I found an AEM Dry Panel Filter online for $30 and decided to drop it in.

TLDR: Panel Filter got dirty, Decided to try an AEM Drop in

Approach: I decided to take the most scientific approach I could in replacing the part and testing its effects. I was expecting NO ADDED HORSEPOWER from the intake and without other modifications paying for dyno time isn't really viable at this time. Unfortunately I do not have any aftermarket gauges or an AccessPort to read air fuel ratios (both are on the list of upgrades but not until the suspension and brakes are sorted out) So I determined that the parts I could test without any extra hardware were the noise levels and the fuel economy. That being said I don't know if it had any impact on the horsepower or torque so please don't ask, /rant/ I have read too many threads about some guy that slapped a new intake/filter/duct/vent/ on their WRX and all the sudden it got LOTS more horsepower /rant over/ this is not one of those threads.

Procedure: To test for noise I pulled out my sound tester and placed it 1.5 feet above and 1 foot to the left of my intake air dam. I choose that location because I could rest the tester on my workbench and handle the procedure without extra help. To isolate any chance of vibration adding noise to my tests I used a 1/4 inch Sorbonne noise isolation sheet to rest my tester on. I tested the intake noise level with the dirty factory filter first, after starting and allowing the engine to come to running temps I opened the throttle to 4,500 RPM. The 1st set of tests yielded a total volume of 82 decibels. after allowing the engine to cool enough to get my hand to the side of the air box I removed the box, removed the muddy old filter and test fitted the AEM filter, It only fits in one direction and is a nice tight fit around the air box. after re-assembling the air box and installing it back into its factory location I proceeded to test the volume again. This time with the AEM filter it produced 1 decibel more volume than the factory panel. Before taking it out on the road I unplugged the negative terminal on the battery and held the brake pedal until the lights went dim. this reset should allow the ECU to relearn the new airflow characteristics of the new panel filter. I drove the car to and from work and in the canyons about 120 miles total to allow the ECU to relearn.

Fuel Economy: MPG tests were based on my previous weeks commute to work, my commute has a 14 mile stretch of relatively open highway, I set cruise control at 3,000RPM and reset the fuel economy counter to find a HIGHWAY ONLY fuel economy. with the factory filter I achieved a 27.5 MPG average on the highway stretch of my commute. After I sucked up that dirt I noticed my fuel economy dropped to nearly 23 MPG. after installing the clean AEM panel filter I found that I achieved an even average of 29MPG.

Conclusion: The increased fuel economy was around 5 percent, while that figure seems important it is well within the standard deviation and it is possible that the change may be due to other non-related conditions. The increase in intake noise I am attributing to the difference between a clean and a dirty filter and would for all intensive purposes have little to no effect on heard noise in the cabin. That being said my butt dyno is rather happy with the switch even if it is just knowing that the air filter isn't covered in dry mud. I could swear up and down that the throttle response is better but that again is probably just due to the filter being clean. As far as the savings between a washable dry filter and a factory paper filter, after 20,000 miles the washable filter should prove its worth (assuming I don't replace it with a performance intake before the 30,000 mile mark)

When I get my AP I might stick the dirty old filter in and get some more precise AFR numbers but for now I am enjoying a clean filter.

If you choose to do the same it is highly recommended that you reset the ECU whenever changing intake or exhaust components, even replacing a dirty filter with a clean factory one.

Wow,that was an impressive amount of information on a drop in filter! I hope all of your mods/upgrades have this level of research and information! I look forward to your build thread.

BLAZE2099

12-17-2013 06:29 PM

Good read, thank you!

arcticscythe

12-17-2013 07:02 PM

I'm glad it was worth reading, I fully intend to write up any modification I handle on my own, and maybe some that I take to the shop. I have always been big on reliable information and I follow a scientific method where possible. There is so much poorly collected information on the internet especially when it comes to cars I just want to help the community out in the best method I can.

I've only had the new filter in for a few days but after a few weeks ill amend my post with new information and updates.

Pre-Story: About 2 weeks ago I drove my 2013 WRX through a dry sandy valley, when a large bit of wind kicked up the light sand that was piled on the side of the canyon, aside from coating the front of my car in a thin sandy coat I was sure that I sucked up a good bit, When I was washing/waxing the WRX over the weekend I noticed that the air dam on the front bumper had gotten rather muddy from the wash and when I removed it for cleaning I could see the same muddy brown crud coating a large portion of the panel filter. I went down to my local autoparts store and found 4 panels that fit, 3 were paper filters much like the OEM and 1 was a fiberglass filter that required oiling. After reading numerous CIA threads I decided that oiled filters were not for me and decided to go with a dry type panel filter. I found an AEM Dry Panel Filter online for $30 and decided to drop it in.

TLDR: Panel Filter got dirty, Decided to try an AEM Drop in

Approach: I decided to take the most scientific approach I could in replacing the part and testing its effects. I was expecting NO ADDED HORSEPOWER from the intake and without other modifications paying for dyno time isn't really viable at this time. Unfortunately I do not have any aftermarket gauges or an AccessPort to read air fuel ratios (both are on the list of upgrades but not until the suspension and brakes are sorted out) So I determined that the parts I could test without any extra hardware were the noise levels and the fuel economy. That being said I don't know if it had any impact on the horsepower or torque so please don't ask, /rant/ I have read too many threads about some guy that slapped a new intake/filter/duct/vent/ on their WRX and all the sudden it got LOTS more horsepower /rant over/ this is not one of those threads.

Procedure: To test for noise I pulled out my sound tester and placed it 1.5 feet above and 1 foot to the left of my intake air dam. I choose that location because I could rest the tester on my workbench and handle the procedure without extra help. To isolate any chance of vibration adding noise to my tests I used a 1/4 inch Sorbonne noise isolation sheet to rest my tester on. I tested the intake noise level with the dirty factory filter first, after starting and allowing the engine to come to running temps I opened the throttle to 4,500 RPM. The 1st set of tests yielded a total volume of 82 decibels. after allowing the engine to cool enough to get my hand to the side of the air box I removed the box, removed the muddy old filter and test fitted the AEM filter, It only fits in one direction and is a nice tight fit around the air box. after re-assembling the air box and installing it back into its factory location I proceeded to test the volume again. This time with the AEM filter it produced 1 decibel more volume than the factory panel. Before taking it out on the road I unplugged the negative terminal on the battery and held the brake pedal until the lights went dim. this reset should allow the ECU to relearn the new airflow characteristics of the new panel filter. I drove the car to and from work and in the canyons about 120 miles total to allow the ECU to relearn.

Fuel Economy: MPG tests were based on my previous weeks commute to work, my commute has a 14 mile stretch of relatively open highway, I set cruise control at 3,000RPM and reset the fuel economy counter to find a HIGHWAY ONLY fuel economy. with the factory filter I achieved a 27.5 MPG average on the highway stretch of my commute. After I sucked up that dirt I noticed my fuel economy dropped to nearly 23 MPG. after installing the clean AEM panel filter I found that I achieved an even average of 29MPG.

Conclusion: The increased fuel economy was around 5 percent, while that figure seems important it is well within the standard deviation and it is possible that the change may be due to other non-related conditions. The increase in intake noise I am attributing to the difference between a clean and a dirty filter and would for all intensive purposes have little to no effect on heard noise in the cabin. That being said my butt dyno is rather happy with the switch even if it is just knowing that the air filter isn't covered in dry mud. I could swear up and down that the throttle response is better but that again is probably just due to the filter being clean. As far as the savings between a washable dry filter and a factory paper filter, after 20,000 miles the washable filter should prove its worth (assuming I don't replace it with a performance intake before the 30,000 mile mark)

When I get my AP I might stick the dirty old filter in and get some more precise AFR numbers but for now I am enjoying a clean filter.

If you choose to do the same it is highly recommended that you reset the ECU whenever changing intake or exhaust components, even replacing a dirty filter with a clean factory one.

I have not yet tuned the car for the drop in panel filter. I do plan on purchasing a Cobb AP after the holidays and in all reality I will probably take the opportunity to order a cobb or AEM cold air intake.

I did however reset the ECU as part of my replacement process so hopefully the ECU is able to learn the characteristics of a slightly different air filter. I'm my case I would think that the difference in airflow between the nasty old filter and even a clean new paper filter would cause a lean condition if the ECU had learned from the dirty old filter. (ECU reads dirty filter airflow in liters per minute and clean filter in *more* Liters per minute )I am operating under the assumption that even a " high flow* " panel filter would perform in a fashion very similar to the factory paper filter with the only advantage being that its washable, im not sure I believe that it would allow the engine to suck in more air.

Again I do plan on tuning in the near future but I want to make sure I have all my holiday gifts paid off before I buy more toys for myself : )

Haw1es

12-18-2013 04:45 PM

I think some aftermarket filters do have a higher CFM than a clean stock paper filter. Our ECUs cant handle a little increased airflow >_<

That what ive heard, that some aftermarket filters offer a tiny amount of extra flow.

I'm kind in the engine = air pump camp as far as intake and exhaust modifications but if the MAF cant get a good read or the ECU cant handle the extra air I can definitely see that being a problem.

The more I read the more i want to pickup my Access Port and take some AFR readings already....hopefully after the holiday ill have a bit of spare cash and I might end up getting the Access Port before my suspension even if its just to get more info about how everything running. >_<

boo-key

12-18-2013 05:06 PM

[quote=arcticscythe;414762]

The more I read the more i want to pickup my Access Port and take some AFR readings already. >_<[/quote]

The accessport does not read afr's.

brfatal

12-18-2013 05:22 PM

It does, but they aren't accurate enough to waste your time looking at.

arcticscythe

12-18-2013 05:22 PM

I was under the impression that I would need to add/replace a wide band sensor and that the Cobb AP V3 would allow me to take readouts from the wide band sensor using their gauge display.

This page shows Air/Fuel on the gauge display -- [url]http://www.cobbtuning.com/Accessport-s/70458.htm#/v/accessport/features/V3[/url]

If not that's not such a big deal , I can always go the old school route and get a separate controller/display for a wide band , not sure if I want to go through all that trouble at the moment.

I think ill shoot Cobb an email this afternoon maybe they have a solution to verify that everything is running correctly.

If the V3 cannot readout the AFR maybe ill just pickup an intake with a Cobb OTS map like the AEM CIA, of the Cobb SF. /sarcasm/ Darn I guess ill have to upgrade the intake too just so everything is happy /end sarcasm/ they were on the list anyway : )

arcticscythe

12-18-2013 05:34 PM

[quote=brfatal;414778]It does, but they aren't accurate enough to waste your time looking at.[/quote]

Is it that the AP CAN read the AFR but the stock sensor isn't very accurate or that the Cobb AP isn't an accurate tool to read AFR period. If its a matter of swapping the sensor that's not such a big deal I would just need to add it to the to-do list.

NeverSummer

12-18-2013 05:37 PM

[quote=arcticscythe;414786]I was under the impression that I would need to add/replace a wide band sensor and that the Cobb AP V3 would allow me to take readouts from the wide band sensor using their gauge display.

This page shows Air/Fuel on the gauge display -- [url]http://www.cobbtuning.com/Accessport-s/70458.htm#/v/accessport/features/V3[/url]

If not that's not such a big deal , I can always go the old school route and get a separate controller/display for a wide band , not sure if I want to go through all that trouble at the moment.

I think ill shoot Cobb an email this afternoon maybe they have a solution to verify that everything is running correctly.

If the V3 cannot readout the AFR maybe ill just pickup an intake with a Cobb OTS map like the AEM CIA, of the Cobb SF. /sarcasm/ Darn I guess ill have to upgrade the intake too just so everything is happy /end sarcasm/ they were on the list anyway : )[/quote]

Nope. Cobb only supports aem cai and Cobb sf intakes. Instead of the drop in filter which does NOTHING, you should have gotten the aem cai. The Cobb ap port can not change values in the ecu.

My intention with the AEM panel filter was really just to replace an old gross paper one. I dont expect Cobb to have a OTS map for the AEM panel filter i was just hoping that the V3 could give me AFR so i could monitor it myself and make sure I wasn't excessively lean. I do plan on the Cobb SF or AEM CAI in the next few months but I wanted to put a clean replacement for now.

This close to the holidays I couldn't drop $300 for a CAI, but it'll happen eventually... and by eventually I mean really soon ; )

BLAZE2099

12-18-2013 06:24 PM

Would a used safc give you what you're looking for. Just to read though and not to adjust.